Garden: Know how and when to water plants this summer

So far this spring, rainfall has been fairly reliable and adequate and air temperatures have been moderate, eliminating the need for frequent watering of most outdoor plants in Greater Columbus.

Most gardens will, however, need to be irrigated more frequently at some point this summer when air temperatures heat up and rainfall becomes more spotty or even nonexistent for a period of time.

Understanding how and when to provide water to the plants in your care is critical tomaintaining plant health and growth.

How much water is needed?

Most plants growing in the ground need a minimum of 1 inch of water each week to thrive in the warm temperatures of summer. This is true for most plants, including vegetables, flowers, turf, herbaceous perennials, shrubs and even trees.

If rainfall does not provide at least 1 inch of water to your plants each week, you will need to provide supplemental irrigation.

This is even more critical when air temperatures are warmer and plants are under heat stress. One inch of water is a minimum and some plants, such as tomatoes, need more than an inch of water per week in order to thrive and produce fruit.

Many vegetable plants will require more water when they are in the flowering and fruit production phase of development.

If you don’t already have one, a rain gauge is a great tool to help you determine if last night’s rain shower was adequate or if you need to provide supplemental irrigation.

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Rainfall amounts vary widely in a geographic region, especially in summer, and a rain gauge will help you keep track of the amount of rainfall that actually falls on your plants.

Container plants need special care

Vegetables, herbs and annual flowers planted in containers will need more water more frequently, particularly pots smaller than 10 inches in diameter. Containers in full sun will dry out more quickly than those in locations which receive some shade, such as porches.

Unglazed clay pots tend to dry out more quickly than containers made of other materials. Raised beds are like large containers, and if your raised beds are less than 18 inches deep, plants growing in these beds will likely need to be watered more frequently than plants growing in the ground.

Water the soil, not the plants

If you water with a hose or watering can, be sure to direct the water directly to the soil, and not on the foliage of the plants. Watering the soil is the most effective and efficient method to provide moisture to a plant.

Water on foliage evaporates and can even burn foliage on some plants when sun hits the water droplets. Except on turf, avoid the use of overhead sprinklers as they provideperfect conditions for foliar diseases to develop, especially in susceptible vegetable andherbaceous perennial plants.

A long-handled watering wand is a good investment as it allows you to more easily direct the flow of the water to the soil surface and regulate the flow.

Using a soaker hose with its many small holes which deliver water slowly over time to the root zone of your plants is a very effective method for watering both in-ground plantings and raised beds. And the best part of using a soaker hose is that you don’t have to stand out in the hot sun while you are watering your plants!

A drip or trickle irrigation system is also a very efficient method for watering plants, particularly vegetable crops. Plants watered with drip irrigation systems yield better and have fewer diseases than plants irrigated by other methods.

Less water will be needed when using a drip irrigation system since water is supplied directly to the root zone where the plant needs it. You can even supply fertilizer through a drip irrigation system.

Drip irrigation systems are easy to set up and the necessary parts can be purchased at some local garden centers and through many sources online. A complete guide to building and operating a home garden irrigation system can be found here: go.osu.edu/homegardenirrigationsystem.

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Conserving water

One of the most effective strategies for conserving water when irrigating plants is the use of mulches. Whether you use black-plastic mulch or landscape fabric in the vegetable garden, or compost or shredded-hardwood mulches in your flower beds, plants grown in soil with a 3-inch layer of mulch will require less frequent irrigation.

The use of water from rain barrels connected to down spouts of a structure can provide an inexpensive source of supplemental water, especially for nonedible food crops, such as flowers, shrubs and trees.

When using rain-barrel water to water food crops, consider disinfecting the water in the rain barrel with a food grade sanitizer before applying to food crops. And always water the soil, and not the edible parts of the plant.

Mike Hogan is Extension Educator, Agriculture and Natural Resources and associate professor with Ohio State University Extension.

[email protected]

This article originally appeared on The Columbus Dispatch: Garden: Knowing how and when to water gardens this summer